The present invention relates to a brake mechanism for fastening to a particular part of a wheeled apparatus, for example, the hand grip of a wheeled chair, for controlling movement of the wheels.
A variety of wheeled chairs have been disclosed, and intensively used to help people walk. U.S. Pat. Nos. 4,907,794 and 5,020,560 disclose different folding collapsible wheeled chairs. Because these wheeled chairs are moved by means of wheels, brake means should be installed. However, regular brake means for this purpose can only temporarily stop the wheeled chair. Recently, dual braking mode brake means with temporary braking function and continuous braking function have been developed. When the brake lever is pushed downwards, the brake means is shifted to the continuous braking position (the braking status remains unchanged when the user releases the brake lever). Similar disclosures are seen in U.S. Pat. No. 5,279,180 and Taiwan Pat. No. 199339.
U.S. Pat. No. 5,279,180 discloses another type of brake structure having a driving member. When the brake lever is pushed downwards, the brake lever is "locked" at the base frame to achieve a continuous braking operation. The locking force must surpass the return force of the brake cable so that the brake cable can be maintained pulled up. However, this design has drawbacks as follows:
1. Frequently operating the continuous braking function causes the contact area between the brake lever and the base frame to wear quickly. When the contact area between the brake lever and the base frame starts to wear, the locking of the brake becomes unstable. PA0 2. Because the locking force of the brake lever must surpass the return force of the brake cable, much effort should be employed to the brake lever against the return force of the brake cable when pushing the brake lever downwards, and the applied force greatly increases the rubbing of the brake lever against the base frame.